The present invention relates to a lateral drag link type steering linkage for an automotive vehicle equipped with a vehicle frame and a pair of front wheels and a pair of rear wheels attached thereto.
FIGS. 1 and 2 show a prior art lateral drag link type steering linkage. A steering linkage is provided between a pair of front wheels 1 and a steering gear 2 in such a way that a steering force or motion may be transmitted from the steering gear 2 to the front wheels 1 when required. One end of a pitman arm 3 is connected to the steering gear 2 and the other end thereof is connected through a drag link ball joint 4 to one end of a drag link 5. The other end of the drag link 5 is connected through a drag link ball joint 6 to a tie rod 7 near one end thereof. The tie rod 7 is laterally arranged between the front wheels 1 and is connected at its respective ends to a pair of knuckle arms 10, 11 through a pair of knuckle ball joints 8, 9. The knuckle arms 10, 11 are joined to the respective front wheels 1 in a well known manner. The numeral 12 designates a frame of the automotive vehicle.
Such a conventional steering linkage is so arranged that a rigid axle supports a leaf spring suspension. For example, as shown in FIG. 2, a shaft of the steering gear 2 or any shaft corresponding thereto is arranged outside the leaf spring 13 is such a manner that the drag link 5 does not interfere with the leaf spring 13 at the full bounding thereof by setting a drag link ball joint 4 at a high level. Even if the leaf spring 13 moves up to the position shown by a chain line 13' in FIG. 2, it does not contact the drag link 5. The drag link 5 inclines to one side so that one end of the drag link 5 is far from the tie rod 7.
In such an arrangement of the steering linkage, however, the movement locus M of the drag link ball joint 6 around the knuckel ball joint 9 differs greatly from the movement locus N of the same link ball joint 6 around the drag link ball joint 4 during driving as best shown in FIG. 2. Thus, so called "kick back" transferred from the road to the steering wheel is apt to occur. In particular, as a four wheel drive vehicle which often moves on a poor road is equipped with a differential gear at a front portion thereof, a drag link is usually arranged in a lateral direction of the vehicle frame from a viewpoint of the layout of other members. For such a reason, such a phenomenon cannot be avoided in a four wheel drive vehicle.